Support addition of license header to generated files

modello-core/src/main/java/org/codehaus/modello/ModelloParameterConstants.java

@@ -80,5 +80,12 @@ public class ModelloParameterConstants {
      */
     public static final String XSD_ENFORCE_MANDATORY_ELEMENTS = "modello.xsd.enforce.mandatory.element";
 
+    /**
+     * The license text as string, to be added to generated files, if needed.
+     *
+     * @since 2.3.1
+     */
+    public static final String LICENSE_TEXT = "modello.license.text";
+
     private ModelloParameterConstants() {}
 }

modello-core/src/main/java/org/codehaus/modello/plugin/AbstractModelloGenerator.java

@@ -66,6 +66,8 @@ public abstract class AbstractModelloGenerator implements ModelloGenerator {
 
     private String encoding;
 
+    private String licenseText;
+
     @Inject
     private BuildContext buildContext;
 
@@ -85,6 +87,8 @@ protected void initialize(Model model, Properties parameters) throws ModelloExce
         packageWithVersion = Boolean.valueOf(getParameter(parameters, ModelloParameterConstants.PACKAGE_WITH_VERSION));
 
         encoding = parameters.getProperty(ModelloParameterConstants.ENCODING);
+
+        licenseText = parameters.getProperty(ModelloParameterConstants.LICENSE_TEXT);
     }
 
     protected Model getModel() {
@@ -108,13 +112,27 @@ protected String getEncoding() {
     }
 
     protected String getHeader() {
+        String header = getLicenseHeader();
+        if (header == null) {
+            return getGeneratedHeader();
+        }
+        header += "\n";
+        header += getGeneratedHeader();
+        return header;
+    }
+
+    private String getGeneratedHeader() {
         String version = getClass().getPackage().getImplementationVersion();
         return "=================== DO NOT EDIT THIS FILE ====================\n"
                 + "Generated by Modello" + ((version == null) ? "" : (' ' + version)) + ",\n"
                 + "any modifications will be overwritten.\n"
                 + "==============================================================";
     }
 
+    private String getLicenseHeader() {
+        return licenseText;
+    }
+
     protected boolean isClassInModel(String fieldType, Model model) {
         try {
             return model.getClass(fieldType, generatedVersion) != null;

modello-maven-plugin/src/main/java/org/codehaus/modello/maven/AbstractModelloGeneratorMojo.java

@@ -25,6 +25,10 @@
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.InvalidPathException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -95,6 +99,15 @@ public abstract class AbstractModelloGeneratorMojo extends AbstractMojo {
     @Parameter
     private List<String> packagedVersions = new ArrayList<String>();
 
+    /**
+     * The contents of license header, verbatim. It may be file path and if file exists, will be loaded up. Otherwise,
+     * the contents of this parameter is reused as-is.
+     *
+     * @since 2.3.1
+     */
+    @Parameter
+    private String licenseText;
+
     /**
      * @since 1.0.1
      */
@@ -160,11 +173,29 @@ public void execute() throws MojoExecutionException {
 
         parameters.setProperty(ModelloParameterConstants.PACKAGE_WITH_VERSION, Boolean.toString(packageWithVersion));
 
-        if (packagedVersions.size() > 0) {
+        if (!packagedVersions.isEmpty()) {
             parameters.setProperty(
                     ModelloParameterConstants.ALL_VERSIONS, StringUtils.join(packagedVersions.iterator(), ","));
         }
 
+        if (licenseText != null && !licenseText.trim().isEmpty()) {
+            String license = "";
+            try {
+                Path licenseFile = Paths.get(licenseText);
+                if (Files.isRegularFile(licenseFile)) {
+                    license = String.join("\n", Files.readAllLines(licenseFile));
+                }
+            } catch (IOException e) {
+                throw new MojoExecutionException("Could not load up license text from " + licenseText, e);
+            } catch (InvalidPathException e) {
+                // ignore, is verbatim text probably
+            }
+            if (license.isEmpty()) {
+                license = licenseText;
+            }
+            parameters.setProperty(ModelloParameterConstants.LICENSE_TEXT, license);
+        }
+
         customizeParameters(parameters);
 
         // ----------------------------------------------------------------------